[feature] support processing of (many) more media types (#3090)

* initial work replacing our media decoding / encoding pipeline with ffprobe + ffmpeg

* specify the video codec to use when generating static image from emoji

* update go-storage library (fixes incompatibility after updating go-iotools)

* maintain image aspect ratio when generating a thumbnail for it

* update readme to show go-ffmpreg

* fix a bunch of media tests, move filesize checking to callers of media manager for more flexibility

* remove extra debug from error message

* fix up incorrect function signatures

* update PutFile to just use regular file copy, as changes are file is on separate partition

* fix remaining tests, remove some unneeded tests now we're working with ffmpeg/ffprobe

* update more tests, add more code comments

* add utilities to generate processed emoji / media outputs

* fix remaining tests

* add test for opus media file, add license header to utility cmds

* limit the number of concurrently available ffmpeg / ffprobe instances

* reduce number of instances

* further reduce number of instances

* fix envparsing test with configuration variables

* update docs and configuration with new media-{local,remote}-max-size variables

1 files changed, 0 insertions, 114 deletions

diff --git a/vendor/github.com/go-errors/errors/stackframe.go b/vendor/github.com/go-errors/errors/stackframe.go
deleted file mode 100644
index f420849d2..000000000
--- a/vendor/github.com/go-errors/errors/stackframe.go
+++ /dev/null
@@ -1,114 +0,0 @@
-package errors
-
-import (
-	"bufio"
-	"bytes"
-	"fmt"
-	"os"
-	"runtime"
-	"strings"
-)
-
-// A StackFrame contains all necessary information about to generate a line
-// in a callstack.
-type StackFrame struct {
-	// The path to the file containing this ProgramCounter
-	File string
-	// The LineNumber in that file
-	LineNumber int
-	// The Name of the function that contains this ProgramCounter
-	Name string
-	// The Package that contains this function
-	Package string
-	// The underlying ProgramCounter
-	ProgramCounter uintptr
-}
-
-// NewStackFrame popoulates a stack frame object from the program counter.
-func NewStackFrame(pc uintptr) (frame StackFrame) {
-
-	frame = StackFrame{ProgramCounter: pc}
-	if frame.Func() == nil {
-		return
-	}
-	frame.Package, frame.Name = packageAndName(frame.Func())
-
-	// pc -1 because the program counters we use are usually return addresses,
-	// and we want to show the line that corresponds to the function call
-	frame.File, frame.LineNumber = frame.Func().FileLine(pc - 1)
-	return
-
-}
-
-// Func returns the function that contained this frame.
-func (frame *StackFrame) Func() *runtime.Func {
-	if frame.ProgramCounter == 0 {
-		return nil
-	}
-	return runtime.FuncForPC(frame.ProgramCounter)
-}
-
-// String returns the stackframe formatted in the same way as go does
-// in runtime/debug.Stack()
-func (frame *StackFrame) String() string {
-	str := fmt.Sprintf("%s:%d (0x%x)\n", frame.File, frame.LineNumber, frame.ProgramCounter)
-
-	source, err := frame.SourceLine()
-	if err != nil {
-		return str
-	}
-
-	return str + fmt.Sprintf("\t%s: %s\n", frame.Name, source)
-}
-
-// SourceLine gets the line of code (from File and Line) of the original source if possible.
-func (frame *StackFrame) SourceLine() (string, error) {
-	if frame.LineNumber <= 0 {
-		return "???", nil
-	}
-
-	file, err := os.Open(frame.File)
-	if err != nil {
-		return "", New(err)
-	}
-	defer file.Close()
-
-	scanner := bufio.NewScanner(file)
-	currentLine := 1
-	for scanner.Scan() {
-		if currentLine == frame.LineNumber {
-			return string(bytes.Trim(scanner.Bytes(), " \t")), nil
-		}
-		currentLine++
-	}
-	if err := scanner.Err(); err != nil {
-		return "", New(err)
-	}
-
-	return "???", nil
-}
-
-func packageAndName(fn *runtime.Func) (string, string) {
-	name := fn.Name()
-	pkg := ""
-
-	// The name includes the path name to the package, which is unnecessary
-	// since the file name is already included.  Plus, it has center dots.
-	// That is, we see
-	//  runtime/debug.*T·ptrmethod
-	// and want
-	//  *T.ptrmethod
-	// Since the package path might contains dots (e.g. code.google.com/...),
-	// we first remove the path prefix if there is one.
-	if lastslash := strings.LastIndex(name, "/"); lastslash >= 0 {
-		pkg += name[:lastslash] + "/"
-		name = name[lastslash+1:]
-	}
-	if period := strings.Index(name, "."); period >= 0 {
-		pkg += name[:period]
-		name = name[period+1:]
-	}
-
-	name = strings.Replace(name, "·", ".", -1)
-	return pkg, name
-}